A graphite film offers high heat dissipation performance due to its high heat conductivity, but has low surface activity and therefore has poor adhesion to resins or metals or other materials. For example, when a graphite film is used as a heat dissipator for substrates, a resin layer made of a resin such as an epoxy resin may be directly formed on the surface of the graphite film, but void formation or separation is likely to occur between the graphite film and the resin layer when molding is performed under conditions where pressure or heat is applied. Further, when such a graphite film having a resin layer formed on the surface thereof is exposed to high temperature in, for example, a soldering process, there is a case where separation or delamination occurs between the graphite film and the resin layer due to the difference in linear expansivity between the graphite film and the resin because the adhesion strength between the graphite film and the resin layer is poor.
On the other hand, when combined with a metal plate, a graphite film may be brazed with solder or the like but is poor in affinity for solder. Therefore, it is difficult to join a graphite film to a metal plate with solder.
In order to solve such problems, a method has been disclosed in which a metal layer is formed on the surface of a graphite film to form a graphite composite film (Patent Document 1).    Patent Document 1: JP-A-2001-177024